Method for making a blocked amine

ABSTRACT

A single component epoxy coating precursor and a method for making such a precursor, a low VOC epoxy coating and a method for making such a coating, and a method for making a blocked amine which is more stable than previously known ones.  
     The single component epoxy coating precursor includes an epoxy resin, a first solvent, and a blocked amine. The single component epoxy coating precursor has a viscosity after 30 days at a temperature of 55° C. of less than 16 stokes.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is a divisional of U.S. patent application Ser.No. 09/776,489 filed Feb. 2, 2001, entitled “SINGLE COMPONENT ROOMTEMPERATURE CURABLE LOW VOC EPOXY COATINGS”.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to epoxy coatings, andmore particularly to the use of blocked amine compounds in making epoxycoatings.

[0003] Curable epoxy resin systems are known. Conventional two componentepoxy resin systems involve mixing of the epoxy resin and hardener andsubsequent application of such mixtures as coatings by varioustechniques. Once mixed, such systems have short pot lives and must beused within a few hours.

[0004] As a result, efforts have been made to develop what are calledone component systems. In one component systems, the curing agent ismixed with the epoxy but is inactive. It can be activated at a latertime. One type of one component system involves the use of elevatedtemperature to activate the cross-linking reaction. However, the use ofhigh temperatures is undesirable in many applications.

[0005] Another type uses latent cure, blocked amine systems in anattempt to alleviate the problem of reduced shelf life. In blocked aminesystems, the amine is reacted with a ketone or aldehyde to form ablocked amine which is mixed with the epoxy resin. The system isactivated by the addition of water, typically in the form of ambientmoisture. This reverses the blocking reaction, forming the amine and theketone or aldehyde. The amine then reacts with the uncured epoxy resin,and the ketone or aldehyde either evaporates or co-reacts with theepoxy. In the absence of moisture, such blocked amines systems afford aslight improvement in storage stability over conventional two componentsystems. However, commercial ketimine-based epoxy resin systems stillsuffer from limited storage stability, typically having a pot life ofless than 24 hours. (Shell, 1986, EPON Curing Agents).

[0006] Furthermore, many systems include volatile organic compounds(VOC) or hazardous air pollutants (HAP), which are regulated. Commercialketimine-based epoxy resin systems have elevated levels of VOCs,generally in excess of 3.5 lbs/gal. Under the current VOC standard formany industrial and maintenance coating applications, the limit is 3.1lbs/gal of VOCs. This limit is likely to be reduced in the future toless than 2.8 lbs/gal of VOCs.

[0007] The use of ketimines as curing agents for epoxy resins isdescribed in R. T. Holm, “Ketimines as Latent Epoxy Curing Agents,” J.of Paint Tech., Vol. 39, No. 509, June 1967, pp. 385-388. The VOC levelsof these compounds is over 3.5 lbs/gal. The reported viscosity of theformulations containing the various ketimines ranged from about 3 toabout 36 stokes after storage for 20 days at 25° C. However, theseformulations do not provide the long term stability desired forcommercial products. The long term stability of the formulations can beevaluated using accelerated aging testing at 55° C. Two weeks storage at55° C. is equivalent to a shelf life of about six months, while 30 daysstorage is equivalent to a shelf life of over 1 year. The shelf life at55° C. is estimated to be only about 12% of the value at 25° C.

[0008] British Patent No. 960,236, which is incorporated herein byreference, attempts to improve the shelf life of ketimine-based singlecomponent epoxy coatings by using hydroxyl-containing imines as blockedcuring agents. The imines are obtained by reacting one or more iminespossessing at least one amino hydrogen and one or more compounds havingat least one epoxy group. No shelf life or VOC level is reported forthese formulations. U.S. Pat. No. 5,837,785, which is incorporatedherein by reference, discloses the use of heterocyclic containing curingagents for use in single component epoxy resin compositions. Theheterocycle-containing compound has a backbone chain selected from thegroup consisting of polyether, polyvinyl, polyester, polyamide,polycarbonate, and novalac chains and at least two heterocyclic groupsof the following general formula as side chains:

[0009] wherein R¹ and R² may be the same or different and eachrepresents hydrogen, straight chain or branched C₁ to C₆ alkyl oralkenyl, or C₆ to C₈ aryl; or R¹ and R² taken together with the adjacentcarbon atom, represents C₅ to C₇ cycloalkyl: R³ represents C, to C₁₀alkylene. A shelf life of 6 months at 40° C. is reported, but no VOClevel is given. The viscosity of coating formulations is not disclosed,but it appears to be high for conventional coating applications.

[0010] Therefore, there is a need for a single component epoxy coatingprecursor having improved shelf life and a method for making such aprecursor. There is also a need for a low VOC epoxy coating and for amethod of making such a coating. There is also a need for a method ofmaking a blocked amine which can be used in a single component epoxycoating precursor.

SUMMARY OF THE INVENTION

[0011] The present invention solves this need by providing a singlecomponent epoxy coating precursor and a method for making such aprecursor, a low VOC epoxy coating and a method for making such acoating, and a method for making a blocked amine which is more stablethan previously known ones.

[0012] The single component epoxy coating precursor includes an epoxyresin, a first solvent, and a blocked amine. The single component epoxycoating precursor has a viscosity after 30 days at a temperature of 55°C. of less than 16 stokes. It can have a viscosity after 30 days at atemperature of 55° C. of less than 13 stokes, or a viscosity after 30days at a temperature of 55° C. of less than 7 stokes.

[0013] The method for making a single component epoxy coating precursorincludes drying an epoxy resin and a blocked amine, combining and mixingthe epoxy resin, the blocked amine, and a first solvent to form thesingle component epoxy coating precursor, wherein the single componentepoxy coating precursor has a viscosity after 30 days at a temperatureof 55° C. of less than 16 stokes. It can have a viscosity after 30 daysat a temperature of 55° C. of less than 13 stokes, or a viscosity after30 days at a temperature of 55° C. of less than 7 stokes. This level ofviscosity stability at 55° C. generally corresponds to over one year ofshelf life at room temperature storage conditions.

[0014] A reactive diluent optionally can be added to the singlecomponent epoxy coating precursor. Reactive diluents include, but arenot limited to, modified glycidyl ethers, acrylates, methacrylates,urethane acrylates and combinations thereof. A water scavengeroptionally can be added to the single component epoxy coating precursor.Water scavengers include, but are not limited to, molecular sieves,monocyclic bifunctional oxazolidines and combinations thereof. Pigmentsmay be optionally added to the single component epoxy coating precursor.Pigments include, but are not limited to, titanium dioxide, diarylideyellow, iron oxide, raw umber, burnt umber, phthalocyanine blue, cobaltblue, chinese blue, phthalocyanine green, toluidine red, quinacridonered, dicerylide orange, carbon black, furnale black, lampblack, leafingaluminum and non-leaving aluminum.

[0015] Other formulating aids such as wetting agents, flow and rheologymodifiers, light stability additives, etc., known in the art can be alsoincorporated.

[0016] First solvents which are useful in the present invention include,but are not limited to acetone, p-chlorobenzotrifluoride, t-butylacetate, methyl isobutyl ketone, methyl propyl ketone and combinationsthereof.

[0017] Epoxy resins include, but are not limited to, aliphatic epoxyresins, cycloaliphatic epoxy resins, aromatic epoxy resins andcombinations thereof.

[0018] The single component epoxy coating precursor can have a VOC levelof less than about 3 lbs/gal, or a VOC level of less than about 2.8lbs/gal.

[0019] The method of making a low VOC epoxy coating includes drying anepoxy resin and a blocked amine, combining and mixing the epoxy resin,the blocked amine, and a first solvent to form the single componentepoxy coating precursor, the single component epoxy coating precursorhaving a VOC level of less than about 3 lbs/gal, and exposing the singlecomponent epoxy coating precursor to water, the single component epoxycoating precursor and water reacting to form the low VOC epoxy coating.The water can be present in any form desired, including, but not limitedto liquid water, and moisture in the air. The VOC level can be less thanabout 2.8 lbs/gal. The single component epoxy coating precursordescribed above and the blocked amine described below can be used tomake the low VOC epoxy coating.

[0020] The method for making the blocked amine includes mixing a solventcapable of forming an azeotrope with water, an amine, and an amineblocker selected from ketones and aldehydes in a reaction vessel to forma reaction mixture. Ambient moisture is removed from the reactionvessel. The amine and the amine blocker are reacted to form the blockedamine and water of reaction, and the water of reaction is removed fromthe reaction mixture while the amine and the amine blocker are reacted.The blocked amine is recovered while maintaining the absence ofmoisture.

[0021] The solvent capable of forming an azeotrope with water includessolvents which can form binary or ternary azeotropes with water. Theseinclude, but are not limited to, toluene, xylene and combinationsthereof.

[0022] The amine can be a polyamine, and it includes but is not limitedto, diethylenetriamine, m-xylylenediamine and combinations thereof.

[0023] The amine blocker is selected from ketones and aldehydes. Theketones and aldehydes may have a molecular weight in the range of about30 to about 600. They may have between about 2 and 14 carbon atoms.Suitable ketones include, but are not limited to, methyl isobutylketone, methyl ethyl ketone, acetone, phorone, heptanedione,tetramethylheptanedione, adamantone, acetonyl acetone,methylpropylketone and combinations thereof. Suitable aldehydes include,but are not limited to benzaldehyde, salicylaldehyde and combinationsthereof.

[0024] The yield of blocked amine can be greater than about 90% of thetheoretical yield, or greater than about 95% of the theoretical yield,or greater than about 97% of the theoretical yield.

[0025] The low VOC epoxy coating includes a reaction product of a singlecomponent epoxy coating precursor and water, the single component epoxycoating precursor comprising an epoxy resin and a blocked amine, thesingle component epoxy coating precursor having a VOC level of less thanabout 3 lbs/gal. The low VOC epoxy coating can have a VOC level of lessthan about 2.8 lbs/gal.

DETAILED DESCRIPTION OF THE INVENTION

[0026] The blocked amines were prepared according to the followingprocedure. The chemicals to be used were dried over molecular sieves. Asolvent capable of forming an azeotrope with water was placed in asuitably sized round bottom flask fitted with a stir bar, magnetic stirplate, heating mantel, reflux condenser, and a Dean-Stark tube. Thesolvent capable of forming an azeotrope with water includes, but is notlimited to, solvents which can form binary or ternary azeotropes withwater. Examples of suitable solvents include, but are not limited to,toluene, xylene and combinations thereof. Toluene was used in theseexperiments as the solvent capable of forming an azeotrope with water.However, it is to be understood that other solvents capable of formingazeotropes with water could also be used. The flask was charged with anamine, a ketone or aldehyde, and a catalyst. Any appropriate catalystcan be used. Generally, acid based catalysts are used, such as p-toluenesulfonic acid. The neck of the reaction flask was wiped with a smallamount of toluene to remove any trace reactants. The flask walls werealso rinsed with a small amount of toluene to minimize exposure of thereactants to ambient moisture.

[0027] After the reaction mixture was added to the flask, it was purgedunder a stream of argon for about 5 minutes while stirring to removeambient moisture and oxygen. The reflux condenser was quickly put inplace and fitted with a gas inlet tube to provide a very slight positivepressure. Alternatively, the reflux condenser can be fitted with adrying tube containing Drierite™ to avoid incorporation of atmosphericwater during the reaction or the subsequent cooling period before theflask is transferred to a distillation apparatus, such as a Rotovap™. Nosignificant difference was observed in the efficiency of azeotrope orthe theoretical mass of water recovered using either arrangement.

[0028] Water flow to the condenser was started, and the reaction flaskand the Dean-Stark tube were wrapped in foil to improve waterazeotroping efficiency. The reaction mixture was then stirred andheated. The mixture was maintained under steady state conditions atabout 116° C. while stirring until either 100% of the theoretical waterof reaction was recovered or until water ceased to azeotrope. Thetemperature will depend on the particular solvent used, and it should beabout the boiling point of the solvent. Here, with toluene as thesolvent (BP about 111° C.), the temperature was about 116° C. Water wasdrained from the Dean-Stark tube as required to prevent overfilling. Thewater of reaction recovered was over 90% of the theoretical amount,typically over 95%, and generally in the range of 96% to 99%.

[0029] At the end of each run, the reaction flask was cooled overnightto room temperature under a slight increase in initial argon pressure orwith the drying tube in place. The positive increase in argon pressurewas to prevent the transport of trap oil and moisture into the reactionflask. After cooling to room temperature, the reaction mixture wasplaced in a Rotovap™ to remove toluene and any unreacted ketone oraldehyde. The bath temperature was 70° C., and the vacuum was increasedslowly to about 2 mm Hg over one hour. The reaction flask was returnedto ambient pressure under argon, removed from the Rotovap™, and placedin a vacuum oven for two days at 70° C. and about 2 mm Hg to remove anyremaining traces of toluene, ketone, or aldehyde. Heat to the vacuumoven was turned off, and the flask was cooled to ambient temperaturewhile maintaining a vacuum. Under a stream of argon, the flask wasreturned to ambient pressure, placed over mole sieves, and capped. Thereaction product was evaluated by infrared analysis for free amine.

[0030] Amines made using this procedure were blocked with a variety ofdifferent ketones and aldehydes. These blocked amines were then used tomake single component epoxy resin precursors. The properties of theprecursors and the coatings made from them were then evaluated.

[0031] The viscosity of the single component epoxy coating precursors intwo solvents, toluene and methylisobutylketone (MIBK), at ambienttemperature was monitored. In addition, the viscosity was monitored forthe epoxy coating precursors in MIBK at 55° C. The accelerated agingsamples were tested on a daily basis for the first 30 days, except onweekends, in order to determine viscosity. The process included removingthe samples from the oven, cooling the samples to room temperature, andthen measuring the samples in direct comparison with Gardner bubbleviscosity tubes. The Gardner bubble viscosity tubes use bubble velocityto determine the viscosity of a sample. The viscosity of the sample isdetermined by finding the standard tube of known viscosity where the airbubble rises at the same rate with that of the test sample. A viscosityof less than 16 stokes is desirable because formulations remainsprayable with conventional spray equipment at this viscosity.

[0032] Coating properties were also evaluated. Draw-down panels wereprepared using a #54 wire bound rod over Bonderite iron phosphatetreated 3″×6″×0.0032″ steel panels and stored at 23° C. and 50% relativehumidity to evaluate cure time and the physical properties of the films.

[0033] The pencil hardness test is described in Paint Testing Manual byH. A. Gardner and G. G. Sward, 13th Ed. (1972) p. 283-284, which isincorporated herein by reference. The ratings from worst to best are:6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, and 6H.

[0034] For the MEK double rubs, a pad made from 10 plies of gauzematerial is attached to the ball end of a 2 lb ball peen hammer. The padis saturated with methyl ethyl ketone (MEK) and rubbed across the coatedsubstrate. A constant back and forth motion is used so that only theweight of the hammer applies the force. One double rub is equal to oneback and forth movement. The movement is continued until the film ismarred and/or begins to be removed by the solvent. One hundred doublerubs are required to pass this test.

[0035] Other standard tests were also run.

[0036] Table 1 shows the formulation of the blocked amine and the epoxycoating precursor, and Tables 2 and 3 show the results of the initialevaluation of the epoxy coating precursors and the epoxy coatings.

[0037] The control formulation containing unblocked diethylenetriamine(DETA) cured in 2 hrs as a thin film from MIBK. The bottled control intoluene gelled in 24 hrs, while the control in MIBK gelled in 48 hoursunder ambient conditions. The control in MIBK stored at 55° C. gelledbetween 1 and 18 hrs.

[0038] In Run 1, an experimental DETA-based curing agent blocked withacetone was used. The experimental DETA-based curing agent was suppliedby Shell with the designation S42686, and contained a mixture of DETA, aproprietary amine, and an alkyl phenol amine (hereafter referred to as“experimental DETA”). The film dried to the touch between 0-24 hrs. Thetoluene and MIBK formulations stored at room temperature gelled in 7days and 9 days, respectively. The accelerated aging sample gelledwithin 24 hrs.

[0039] In Run 2, the experimental DETA-based curing agent was blockedwith MIBK. The drying time for this film was 0-24 hrs. Additional filmswere prepared from this formulation after 3 weeks of aging at roomtemperature and after 16 days at 55° C. The films were dry to the touchat 6 hrs and 2 hrs. The films made from the aged formulations wereblush-free and showed increased gloss with aging of the bottledformulations. Both samples stored at room temperature remained waterlike with no change in viscosity. The accelerated aging sample showed nochange in viscosity until after 15 days. At that time, the viscositywent from about 0.5 to 4.4 stokes within 24 hrs. The sample remainedpourable for 2 more days. Gel time was between 17 and 19 days. Areplicate sample gelled in 22-24 days with a similar cure profile.

[0040] Run 4 used reagent grade DETA blocked with acetone. The dryingtime was slow, over 48 hrs, and the accelerated aging sample gelled inless than 24 hrs. These results are similar to the ones withexperimental DETA. (Run 2).

[0041] DETA (reagent grade) blocked with MIBK was used in Run 5. Twopanels were prepared from this formulation, one fresh and the other agedfor two days. The drying time for the first panel was 0-24 hrs. Thefirst panel showed a slight blush and a low gloss on cure. The secondpanel was monitored at 2 hr intervals to more accurately assess dryingtime. It was dry to the touch in 4 hrs, and showed no blush andexcellent gloss (the wet look) after cure. The bottled samples stored atroom temperature remained water like for over 8 weeks. The acceleratedaging sample gelled after 24 days. A replicate sample also gelled inabout 24 days.

[0042] In Run 6, lysine [H₂N(CH₂)₄CH(NH₂)COOH] was blocked with MIBK.One panel containing a 5% excess of blocked amine based upon 4 primaryamines, and another containing a 5% excess based on all reactivehydrogens (typically 5) were prepared. The panels remained tacky after 8hrs, but were dry to the touch the next morning. Pencil hardness was Bat 24 hrs and 1 week. The panels showed poor resistance to MEK. Theaccelerated aging samples showed no increase in viscosity after 29 days.The sample with the lower concentration of blocked amine gelled in lessthan 6 months, while the sample with the higher level gelled in lessthan 5 months.

[0043] Run 7 involved the use of DETA blocked with phorone[(CH₃)C═CHCOCH═C(CH₃)₂]. Films were dry to the touch in about 8 hrs. Thepanel containing less blocked amine required 8-10 hrs. Pencil hardnesswas <B after 24 hrs and 1 week, and solvent resistance was poor. Theaccelerated aging sample containing the lower level of blocked aminegelled in 25 days. The sample with the higher concentration of blockedamine gelled in 14 days.

[0044] In Run 8, DETA blocked with 2-heptanedione [CH₃(CH2)₄COCH₃] wasused. The films were dry to the touch is 8 hrs. Pencil hardness was B at24 hrs increasing to F at 1 week. MEK resistance was good, especiallyfor the sample with the higher concentration of blocked amine. Thepanels were glossy with a slight blush. The mixtures exhibited“crawling” during application. “Crawling” refers to coatings that drawaway from the surface and leave holes or voids in the coating. Such bareareas are usually related to the wetting properties of the formulation.The accelerated aging sample with the lower concentration of blockedamine gelled in 25 days, while the sample with the higher concentrationgelled at 14 days.

[0045] DETA blocked with tetramethyl heptanedione[(CH₃)₃CCOCH₂COC(CH₃)₃] was used in Run 9 to evaluate the performance ofa diketone. The panels required more than 48 hrs to cure and exhibitedinadequate hardness and solvent resistance. The accelerated agingsamples showed no change in viscosity after 29 days, and did not gel formore than 6 months.

[0046] In Run 10, panels made with DETA blocked with pyruvic aldehydedimethyl acetyl were tacky, but nearly dry to the touch after 8 hrs, andthey were completely dry the next morning. Pencil hardness was B after24 hours for the lower concentration of the blocked amine, and it was Fafter 1 week. The panel made from the higher concentration had a pencilhardness that was <B and H for the same time intervals. The solventresistance was 100 double rubs after 1 week. The panels had a good glossand light blush. The sample with the higher concentration of blockedamine showed a change in viscosity from 0.5 to 13 strokes after 14 daysof accelerated aging, and gelled in 17 days. The sample with the lowerconcentration gelled after more than 30 days.

[0047] Run 11 involved the use of DETA blocked with adamantone. After 8hours, the panels were dry to the touch. The pencil hardness was H, andthe MEK resistance was 100 double rubs after one week. The films weremedium amber with a gloss <90 and a slight blush. The viscosity of theformulation with the lower concentration of blocked amine, increasedfrom 0.5 to 4 stokes in 14 days, and it gelled at between 16 and 21days. The formulation having the higher concentration of blocked aminegelled in 13 days.

[0048] In Run 12, DETA blocked with acetonyl acetone [CH₃COCH₂CH₂COCH₃]was used. The panels remained soft and too tacky for physical evaluationafter one week. After 28 days, no change in viscosity was found in theaccelerated aging samples.

[0049] Meta-xylylenediamine blocked with MIBK was used in Run 13. Within8 to 9 hours the panels were dry to the touch. According to theliterature, blocked amines prepared from meta-xylylenediamine and MIBKdry to the touch in 4 hours at room temperature in the presence of aphenol accelerator. The pencil hardness for the lower concentration ofblocked amine was B after 24 hrs, HB after 48 hrs, and HB after 72 hrs.The MEK double rubs were 50 after 24 hrs, 100 after 48 hrs, and 100after 72 hrs. The panel passed the direct impact tasting, cross hatchand ¼ inch mandrel bend test. The panel showed good gloss andappearance. The panel containing the higher concentration of blockedamine showed a pencil hardness of F after 24 hrs, F after 48 hrs, and Hafter 72 hrs. The MEK double rubs results were 90 after 24 hrs, 100after 48 hrs, and 100 after 72 hrs. This panel also passed the directimpact, cross hatch and ¼ inch mandrel bend tests. No viscosity changeoccurred until after 30 days of accelerated aging. The formulation withthe lower concentration of blocked amine remained unchanged after 40days of accelerated aging and did not gel for more than 6 months. Theformulation having the higher concentration of blocked amine had aviscosity of 2.8 stokes after 40 days, and it did not gel for more than4.5 months.

[0050] Run 14 involved xylylenediamine blocked with diisobutylketone(DIBK). Both panels required more than 48 hrs to dry. They showed apencil hardness of B after one week. At one week, the MEK double rubswere 20 for the lower concentration and 100 for the higherconcentration. The panel passed the other tests. The films were waterwhite with a gloss >90. The aging samples remained unchanged after 13days.

[0051] In summary, Runs 2, 5, 7, 8, 11, and 13 resulted in thin filmcure times of 8 hrs or less. Runs 7, 8, and 11 had reasonable viscositystability at 55° C. The films that produced the best overall physicalproperties, cure rate, and with over 20 days of viscosity stability at55° C. were Runs 2, 5, and 13.

[0052] From these studies, we found that the effectiveness of theblocking agent in providing long term stability for the single componentepoxy coating precursors varies depending on the molecular weight of theblocking agents. A blocking agent having a molecular weight in the rangeof 30 to 600 provides good long term stability.

[0053] The blocked amine used in Run 5, DETA blocked with MIBK, was alsoevaluated with the addition of titanium dioxide (TiO₂). Threeformulations of DETA blocked with MIBK were tested under acceleratedaging conditions: 3.5 g of DETA blocked with MIBK without TiO₂, 3.5 g ofDETA blocked with MIBK with 13% TiO₂, and 3.8 g of DETA blocked withMIBK with 13% TiO₂. The formulations containing TiO₂ gelled in 18 days,as compared to 24 days for the sample without TiO₂. The 3.5 g of DETAblocked with MIBK with 13% TiO₂, was slower to cure than the control.However, by increasing the concentration of the blocked amine (3.8 g ofDETA), a slight improvement in thin film cure times and physicalproperties occurred. Results are further described in Table 4.

[0054] Tests were run with reduced solvent (VOC) levels. The results areshown in Table 5 with regard to storage stability, thin film set timeand the physical properties of formulations. Similar results occurredfor cure and physical properties regardless of the solvent level. Thedata showed that under accelerated aging conditions, a sample containinghalf the MIBK concentration gelled in 12 to 14 days, compared to about24 days for the normal level of MIBK in the control. The controlcontained 4.0 lbs/gal volatiles while the reduced solvent formulationscontained 2.8 lbs/gal of volatiles. TABLE 1 Formulations Run Control 12A 2B 2C 4 5A Amine DETA DETA-based DETA-based DETA-based DETA-basedDETA DETA experimental experimental experimental experimental amineamine amine amine Blocking Agent Acetone MIBK MIBK MIBK Acetone MIBKDraw-down Formulation Solvent MIBK MIBK MIBK MIBK MIBK MIBK Epoxy resinBlocked Amine Aging None 3 weeks at RT 16 days at 55° C. Run 5B 6A 6B 7A7B 8A 8B Amine DETA Lysine Lysine DETA DETA DETA DETA Blocking AgentMIBK MIBK MIBK Phorone Phorone 2-heptanedione 2-heptanedione Draw-downFormulation Solvent MIBK - 10 g MIBK - 10 g MIBK - 10 g MIBK - 10 gMIBK - 10 g MIBK - 10 g Epoxy resin   10 g   10 g   10 g   10 g   10 g  10 g Blocked Amine 3.55 g 4.42 g 3.98 g 4.96 g 3.42 g 4.26 g Aging Run9A 9B 10A 10B 11A 11B Amine DETA DETA DETA DETA DETA DETA Blocking Agenttetramethyl tetramethyl pyruvic aldehyde pyruvic aldehyde AdamantoneAdamantone heptanedione heptanedione dimethyl acetal dimethyl accetalDraw-down Formulation Solvent MIBK - 10 g MIBK - 10 g MIBK - 10 g MIBK -10 g MIBK - 10 g MIBK - 10 g Epoxy resin   10 g 10 g   10 g   10 g   10g   10 g Blocked Amine 5.05 g 6.28 3.51 g 4.38 g 4.26 g 5.30 g Aging Run12A 12B 13A 13B 14A 14B Amine DETA DETA Xylylenediamine XylylenediamineXylylenediamine Xylylenediamine Blocking Agent Acetonyl acetone AcetonylMIBK MIBK DIBK DIBK acetone Draw-down Formulation Solvent MIBK - 10 gMIBK - 10 g MIBK - 10 g MIBK - 10 g MIBK - 10 g MIBK - 10 g Epoxy resin  10 g   10 g  10 g  10 g   10 g   10 g Blocked Amine 3.42 g 4.26 g 3.5g 4.3 g 4.41 g 5.49 g Aging

[0055] TABLE 2 Evaluation Blocked Amines Toluene MIBK MIBK MEK Cross1/4″ Film at RT at RT at 55° C. Time Dry to Pencil Dbl. Hatch MandrelColor Gloss (Daily/ (Daily/ (Daily/ Run (hrs) Touch Hardness Rubs 20 lbs40 lbs Adhesion Bend (1 wk) (1 wk) 24 hrs) 24 hrs) 24 hrs) Control 2 hrs24 2H  Passed Water Gelled Gelled (100) white in 24 hrs in 1-18 blushhrs 48 3H  Gelled in 48 hrs 168- Passed Passed Passed Some Very wk (100)linear slight failure; no stress squares crack- ing 1 0-24 hrs 24 2H 51,soft- Gelled in ening; 24 hrs 24 hr full recovery 48 Passed (100) 168-2H  Passed (100) Passed Partial Passed Failed; Gelled in Gelled wk “rim”lost 7 days in 9 failure adhe- days sion 2A 0-24 hrs 24 Gummy 2B  0Light amber high gloss 48/72 Dry 0/0 1 wk H 100; Passed Passed PassedPassed softening didn't go to bare metal 2 wk H Passed Passed PassedPassed 3 wk 2H  Passed Slight Passed Passed “rim” failure 2B 6 hrs  2Sticky Light amber good gloss  4 Tacky  6 Dry to touch, FP  8 Dry totouch, FP, recovers 2C 2 hrs  2 Dry to Light touch, amber slight no FPblush high gloss (wet look)  4 Dry to touch, slight FP  6 Dry to touch,slight FP  8 Dry to No change touch, after 14 slight days, FP, Passedrecovers aging test 24 Gelled between 17-19 days 48/72 HB  80 PassedPassed Passed Replicate gelled in 22-24 days 96 HB  90 1 wk F 100 PassedPassed Passed 4 24-48 Mod Water amber like hrs ? mod blush orange peel24 Tacky HB  42 Gelled in 24 hrs 48/72 Week- HB 60/75 end 96 Dry  75 1wk F 100 Passed Passed Slight No failure change 2 wk Not moni- tored 5A0-24 Water hrs like 24 HB  35 Clear low gloss slight blush 48/72 B/B42/65 96 B  72 1 wk B  90 2 wk F 100, slight softening 5B 4 hrs  2 Wet 4 Dry to touch, slight FP  6 Dry to touch, slight FP  8 Dry to touch,no FP 24 Clear high gloss no blush 1 wk Passed Slight Passed Gelled in“rim” about 24 failure days 6A 8-24 hrs 24 Dry to <B   <10 touch, slightFP 1 wk B  15 Passed Passed Passed Passed Water Gelled in white lessthan 5 dull months slightly bluish 6B 8-24 hrs 24/48 B  20 72/96 WaterGelled in white less than 6 dull months slightly bluish 1 wk B  15Passed Passed Passed Passed 7A 8-10 hrs 24 <B    <5 1 wk <B    6 FailedFailed Passed Passed Dark >90 Gelled in 25 amber days 7B 8 hrs 24 <B   <5 1 wk B  6 Failed Failed Partial Passed Dark >90 Gelled in 14 Failureamber days 8A 7 hrs  8 7 hrs dry to touch very slight FP 24 B  10 1 wk F100 Passed Failed Passed Passed Yellow <90 Gelled in (dulled medium 14days film) amber blush 8B 6 hrs  6 dry to touch very slight FP 24 B 100(dulled film) 1 wk F 100 (no Passed Failed Passed Failed Yellow <90Gelled in effect medium 25 days amber blush 9A >48 hrs 24 Tacky, GummyGummy FP 1 wk <B   10 Passed Passed Passed Passed Water >90 Gelled inwhite more than 6 months 9B >48 hrs 24 Tacky, Gummy Gummy FP 1 wk <B  15 Passed Passed Passed Passed Gelled in more than 6 months 10A 8-24 hrs 8 nearly dry B <10 1 wk F 100 Passed Passed Passed Passed Light >90Gelled in (dulled amber more than film) blush 30 days 10B 8-24  8 nearlydry 24 <B    5 1 wk H 100 Passed Passed Passed Failed Light <90 Gelledin (dulled amber 17 days film) 11A 8-9 hrs 24 B <10 1 wk H 100 PassedPassed Passed Failed Medium <90 Gelled (dulled amber between film) blush16 and 21 days 11B 8-9 hrs 24 B  10 1 wk H 100 Passed Passed PassedFailed Medium <90 Gelled in (dulled amber 13 days film) 12A >1 wk 12B >1wk 13A 9 hrs 24 B  50 48 HB 100 72 HB 100 1 wk HB 100 Passed PassedPassed Passed Gelled in (dulled more than film) 6 mths 13B 8 hrs 24 B 9048 HB 100 72 HB 100 1 wk HB 100 Passed Passed Passed Passed Gelled in(dulled more than film) 4.5 mths 14A >48 hrs 24 Sticky Sticky 1 wk B  20Passed Passed Passed Passed Water >90 white 14B >48 hrs 24 Sticky Sticky1 wk B 100 Passed Passed Passed Passed Water >90 (slight white dulling)

[0056] TABLE 3 Overall Film Evaluations Based on Visual Observation RunComments  4 Moderate blush  6A Excellent flow upon application, glossdiminished after 8 hrs  6B Excellent flow upon application, glossdiminished after 8 hrs  7A Good flow upon application, slight fisheyes 7B Good flow upon application, slight fisheyes  8A Poor flow, crawling 8B Poor flow, crawling  9A Fairly good flow, slight crawling 10A Goodflow upon application 10B Good flow upon application 11A Good flow uponapplication 11B Good flow upon application 12A Poor flow uponapplication, crawling, fisheyes 12B Poor flow upon application,crawling, fisheyes 14A Very good flow upon application 14B Very goodflow upon application 15A Good flow upon application 15B Good flow uponapplication

[0057] TABLE 4 Physical Data for Epoxy Formulations With and WithoutTitanium Dioxide Hardness (24 hours) FORMULATION Dry to touch MEK DoubleRubs Gel time Ingredients Grams (hours) Day 1 Day 5 Day 6 Day 1 Day 5Day 6 (days) Comments RUN 5 48262-38-16^(A) Passed direct impact, cross48220-44-09 hatch and 1/4″ mandrel bend 3.9 VOC testing after 1 week,gloss and appearence excellent MIBK-DETA 3.5 5 Hours, NFP F H H 100 100100 24 days^(A) MIBK 10 EPON 828 10 TiO2 0 48262-41-13^(B) Sample veryslow to cure after 48220-65-07 2 weeks achieved “HB” pencil 3.9 VOChardness and 100 MEK double rubs with slight dulling. Passed directimpact, cross hatch and mandrel bend tests. MIBK-DETA 3.5 8 hours, sl FPToo <B   <B   Too 4 7 18 days^(B) soft soft MIBK 10 EPON 828 10 TiO2˜13% 48262-41-28 4 hours, 2H H 100 100 18 days >4.0 VOC DTT, FPMIBK-DETA 3.8 Passed direct impact, cross hatch and 1/4″ mandrel bendtesting, gloss and appearence excellent MIBK 10 EPON 828 10 TiO2 ˜13%

[0058] TABLE 5 Physical Data for Epoxy Formulations With DifferentConcentrations of MIBK FORMULATION Hardness (24 hours) MEK Double RubsGel time Ingredients Grams Dry to touch Day 1 Day 5 Day 6 Day 1 Day 5Day 6 (days) Comments Run 2 48262-38-07 Gel 17-19 Passed direct impact,failed 1/4 3.9 VOC days^(A) inch mandrel (rim failure) Gel 22-24 amberappearance with good days^(B) gloss (>90) MIBKxp-DETA 3.5 6 hours B H H40 100 100 MIBK 10 DTT. Very slight FP EPON 828 10 48262-38-25 NONE 2.98VOC MIBKxp-DETA 3.5 9 hours <B   F F 80 100 100 Passed direct impact,failed 1/4 inch mandrel (rim failure) amber appearance with good MIBK 5DTT, slight FP gloss (>90) EPON 828 10 Run 5 48262-38-16 2.98 VOCMIBK-DETA 3.5 5 Hours, NFP F H H 100 100 100  ˜24 days^(C) MIBK 10 EPON828 10 48262-39-07 2.98 VOC MIBK-DETA 3.5 4 hours H 2H  2H  100 100 100Gel time Passed direct impact (20 lbs), 12-14 days^(D) failed directimpact (40 lbs), passed cross hatch, failed 1/4 inch mandrel bend (2wks). Amber appearance slight blush, good gloss (<90) MIBK 5 EPON 828 10

[0059] Another set of tests focused on evaluating reduced VOCformulations. The VOC exempt solvents that were evaluated includedacetone and p-chlorobenzotrifluoride (available as Oxsol 100 fromOccidental Chemical Corp.). Tertiary butyl acetate (t-butyl acetate),for which exempt status is pending, was also evaluated. The nonexemptsolvents included methyl isobutyl ketone (MIBK) and methyl propyl ketone(MPK). The solvents were evaluated in combination with water scavengers,including molecular sieves and Incosol-2® (available from IndustrialCopolymers, Ltd.), and several mono and multifunctional reactivediluents. Incosol-2® is a monocyclic bifunctional oxazolidine thatreacts with water to form a linear aminoalcohol and an aldehyde.

[0060] Eight-five formulations were prepared from xylylenediamineblocked with MIBK. The formulations are shown in Table 6. The materialswere dried over mole sieves prior to use. The epoxy resin (EPON 828available from Miller Stevenson) and the solvent(s) were combined andvortexed for about one minute until the samples were homogenous. Next,the reactive diluent was added, if used. The water scavenger was thenadded, if used. The samples were vortexed again for about 0.5 to 1.0minute each, and the blocked amine was added. The samples were vortexedfor a third time after which aliquots were transferred to 8 ml glassculture tubes, capped and put in the oven at 55° C. for acceleratedaging evaluation. The remaining mixtures were maintained at roomtemperature for approximately 13 to 14 hours.

[0061] The results of the testing of these formulations are shown inTables 7 and 8. TABLE 6 Storage Stability Test Matrix Run 20(MIBK-Xylylenediamine Based System) No Reactive Diluent With 742 746 748757 With Incosol + Incosol − 5.0% Reactive Diluent With Without WithWithout With Without With Without 2.5% Excess Excess Solvent SystemIncosol Incosol Incosol Incosol Incosol Incosol Incosol Incosol AmineAmine MIBK 45 C.  5 C. 55 C. 15 C. 65 C. 25 C. 75 C. 35 C. 2 C. 4 C. MPK47 C.  7 C. 57 C. 17 C. 67 C. 27 C. 77 C. 37 C. OXSOL 100 49 C.  9 C. 59C. 19 C. 69 C. 29 C. 79 C. 39 C. t-Butyl Acetate 51 C. 11 C. 61 C. 21 C.71 C. 31 C. 81 C. 41 C. Acetone 53 C. 13 C. 63 C. 23 C. 73 C. 33 C. 83C. 43 C. No Reactive Diluent With With Mole 742/TMPTA 746/TMPTA748/TMPTA 757/TMPTA Mole S. + S. − 5.0% Reactive Diluent With WithoutWith Without With Without With Without 2.5% Excess Excess Solvent SystemMole S Mole S Mole S Mole S Mole S Mole S Mole S Mole S Amine Amine MIBK46 C.  6 C. 56 C. 16 C. 66 C. 26 C. 76 C. 36 C.  1 C. 3 C. MPK 48 C.  8C. 58 C. 18 C. 68 C. 28 C. 78 C. 38 C. OXSOL 100 50 C. 10 C. 60 C. 20 C.70 C. 30 C. 80 C. 40 C. t-Butyl Acetate 52 C. 12 C. 62 C. 22 C. 72 C. 32C. 82 C. 42 C. Acetone 54 C. 14 C. 64 C. 24 C. 74 C. 34 C. 84 C. 44 C.MIBK/Oxsol 100 85 C.

[0062] TABLE 7 Storage Stability and Physical Property Data Summary ofReduced VOC Formulations Prepared from MIBK-Xylylenediamine ViscosityHard- Hard- Sample at 30 Reactive Solvent Drying ness ness ID Days VOCDiluent Scavenger System DIT 20 DIT 40 Gloss Time (24H) (1 WK)  1C #N/A2.68 None Mole Sieve + 2.5% MIBK Fail Fail 72.5 10-12 H 2H Excess hoursAmine  2C #N/A 2.68 None Incosol + 2.5% MIBK Pass Fail 81.2 10 hours H2H Excess Amine  3C 19 2.7 None Mole Sieve − 5.0% MIBK Pass Fail 7810-12 2H 3H Excess hours Amine  4C #N/A 2.67 None Incosol − 5.0% MIBKPass Fail 85.5 10-12 H 2H Excess Amine hours  5C 5.5 2.69 742 None MIBKPass Pass 47.5 over 10 <B H hours  6C #N/A 2.69 742/TMPTA None MIBK PassFail 103.5 over 10 3H 2H hours  7C 3.2 2.69 742 None MPK Pass Pass 52.5over 10 <B 2H hours  8C #N/A 2.69 742/TMPTA None MPK Pass Fail 101 10-122H 2H hours  9C #N/A 1.33 742 None OXSOL 100 Pass Very 61.7 over 10 <B BSlight hours Fail 10C #N/A 1.47 742/TMPTA None OXSOL 100 Fail Fail 100.2over 10 3H 2H hours 11C #N/A 1.48 742 None t-Butyl Pass Pass 64.2 over10 <B H Acetate hours 12C #N/A 1.61 742/TMPTA None t-Butyl Pass Fail 100over 10 2H 2H Acetate hours 13C 0.85 1.53 742 None Acetone Pass Slight45.1 over 10 H 2H Failure hours 14C #N/A 1.67 742/TMPTA None AcetonePass Fail 102.5 10-12 3H 4H hours 15C 2.8 2.69 746 None MIBK Pass Pass38.3 over 10 <B 2H hours 16C #N/A 2.7 746/TMPTA None MIBK Fail Fail 89.5over 10 2H 2H hours 17C 2.5 2.69 746 None MPK Pass Pass 34.9 over 10 <BF hours 18C #N/A 2.7 746/TMPTA None MPK Pass Fail 80.4 over 10 3H 2Hhours 19C #N/A 1.3 746 None OXSOL 100 Pass Pass 48.2 over 10 <B F hours20C #N/A 1.43 746/TMPTA None OXSOL 100 Pass Fail 97.4 over 10 2H 4Hhours 21C 6.8 1.44 746 None t-Butyl Pass Pass 45.4 over 10 <B 2H Acetatehours 22C #N/A 1.58 746/TMPTA None t-Butyl Pass Fail 95.4 over 10 2H 3HAcetate hours 23C 2.25 1.49 746 None Acetone Pass Pass 25.5 over 10 <B Fhours 24C #N/A 1.63 746/TMPTA None Acetone Pass Fail 97.1 over 10 2H 2Hhours 25C 1.65 2.7 748 None MIBK Pass Pass 17.6 over 10 <B F hours 26C#N/A 2.69 748/TMPTA None MIBK Pass Fail 96.7 over 10 H 2H hours 27C 22.7 748 None MPK Pass Pass 31 over 10 <B HB hours 28C #N/A 2.69748/TMPTA None MPK Pass Fail 82.7 over 10 2H 2H hours 29C 13 1.22 748None OXSOL 100 Pass Pass 29.1 over 10 <B HB hours 30C #N/A 1.42748/TMPTA None OXSOL 100 Pass Fail 90 over 10 2H 2H hours 31C 5.5 1.37748 None t-Butyl Pass Pass 17.3 over 10 <B <B Acetate hours 32C #N/A1.56 748/TMPTA None t-Butyl Pass Pass 93 over 10 2H 2H Acetate hours 33C1.4 1.42 748 None Acetone Pass Pass 33.2 over 10 <B F hours 34C #N/A1.62 748/TMPTA None Acetone Pass Pass 98 over 10 2H 4H hours 35C #N/A2.69 757 None MIBK Pass Fail 60.5 10-12 2H 2H hours 36C #N/A 2.68757/TMPTA None MIBK Pass Fail 99.4 over 10 2H 4H hours 37C 13 2.69 757None MPK Pass Slight 52.6 over 10 2H 2H Failure hours 38C #N/A 2.68757/TMPTA None MPK Pass Fail 99.1 10-12 2H 4H hours 39C #N/A 1.38 757None OXSOL 100 Pass Slight 72 10-12 H 2H Failure hours 40C #N/A 1.48757/TMPTA None OXSOL 100 Pass Pass 99.6 over 10 3H 4H hours 41C #N/A1.53 757 None t-Butyl Pass Very 63.3 over 10 F 2H Acetate Slight hoursFail 42C #N/A 1.62 757/TMPTA None t-Butyl Pass Fail 99.4 over 10 2H 2HAcetate hours 43C 4.4 1.58 757 None Acetone Pass Slight 60.8 10-12 H HFailure hours 44C #N/A 1.68 757/TMPTA None Acetone Pass Fail 101.9 over10 4H 4H hours 45C 5.5 2.69 742 Incosol MIBK Pass Pass 35 10-24 <B Bhours 46C #N/A 2.69 742/TMPTA Mole Sieve MIBK Pass Fail 101.3 10-24 2H4H hours 47C 3.2 2.69 742 Incosol MPK Pass Pass 29.6 10-24 <B <B hours48C #N/A 2.69 742/TMPTA Mole Sieve MPK Pass Fail 98.5 10-24 H 2H hours49C #N/A 1.32 742 Incosol OXSOL 100 Pass Pass 54.5 10-24 <B HB hours 50C#N/A 1.47 742/TMPTA Mole Sieve OXSOL 100 Pass Fail 95.4 10-24 2H 2Hhours 51C 13 1.46 742 Incosol t-Butyl Pass Pass 54.5 10-24 HB HB Acetatehours 52C #N/A 1.61 742/TMPTA Mole Sieve t-Butyl Pass Fail 88.4 10-24 2H2H Acetate hours 53C 0.85 1.52 742 Incosol Acetone Pass Very 42.5 10-24<B F Slight hours Fail 54C 2.8 1.67 742/TMPTA Mole Sieve Acetone PassFail 101.2 10-24 2H 4H hours 55C 2.5 2.69 746 Incosol MIBK Pass Pass32.3 10-24 <B HB hours 56C #N/A 2.7 746/TMPTA Mole Sieve MIBK PassSlight 84 10-24 2H 2H Failure hours 57C 1.65 2.69 746 Incosol MPK PassPass 21 10-24 <B B hours 58C 13 2.7 746/TMPTA Mole Sieve MPK Pass Pass94.5 10-24 2H 4H hours 59C #N/A 1.29 746 Incosol OXSOL 100 Pass Pass45.6 10-24 <B H hours 60C #N/A 1.43 746/TMPTA Mole Sieve OXSOL 100 PassFail 92.3 10-24 H 4H hours 61C 5.5 1.43 746 Incosol t-Butyl Pass Fail38.5 10-24 F H Acetate hours 62C #N/A 1.58 746/TMPTA Mole Sieve t-ButylPass Fail 93.2 10-24 3H 3H Acetate hours 63C 1.25 1.48 746 IncosolAcetone Pass Pass 24.4 10-24 F F hours 64C 3.7 1.63 746/TMPTA Mole SieveAcetone Pass Slight 99.2 10-24 2H 4H Failure hours 65C 2.25 2.7 748Incosol MIBK Pass Pass 16.9 10-24 H B hours 66C #N/A 2.69 748/TMPTA MoleSieve MIBK Pass Pass 94 10-24 H 4H hours 67C 1.4 2.7 748 Incosol MPKPass Pass 15.3 10-24 <B B hours 68C 13 2.69 748/TMPTA Mole Sieve MPKPass Pass 96.2 10-24 H 2H hours 69C #N/A 1.21 748 Incosol OXSOL 100 PassPass 21.6 10-24 <B B hours 70C #N/A 1.42 748/TMPTA Mole Sieve OXSOL 100Pass Fail 91.2 10-24 2H 3H hours 71C 4.7 1.36 748 Incosol t-Butyl PassPass 22.8 10-24 <B F Acetate hours 72C #N/A 1.46 748/TMPTA Mole Sievet-Butyl Pass Pass 83.6 10-24 H 2H Acetate hours 73C 0.65 1.41 748Incosol Acetone Pass Pass 36.9 10-24 <B <B hours 74C 3.7 1.62 748/TMPTAMole Sieve Acetone Pass Pass 91 10-24 H 4H hours 75C #N/A 2.69 757Incosol MIBK Pass Slight 50.7 10-24 2H 2H Failure hours 76C #N/A 2.68757/TMPTA Mole Sieve MIBK Pass Fail 92.1 10-24 2H 4H hours 77C 9 2.69757 Incosol MPK Pass Slight 45.5 10-24 F F Failure hours 78C #N/A 2.68757/TMPTA Mole Sieve MPK Pass Pass 96.8 10-24 2H 4H hours 79C #N/A 1.37757 Incosol OXSOL 100 Pass Pass 65 10-24 H 2H hours 80C #N/A 1.48757/TMPTA Mole Sieve OXSOL 100 Pass Pass 94.9 10-24 2H 4H hours 81C #N/A1.51 757 Incosol t-Butyl Pass Pass 62.7 10-24 <B 2H Acetate hours 82C#N/A 1.62 757/TMPTA Mole Sieve t-Butyl Pass Pass 93.7 10-24 2H >4HAcetate hours 83C 2.5 1.68 757 Incosol Acetone Pass Slight 49.6 10-24 FF Failure hours 84C 5.5 1.63 757/TMPTA Mole Sieve Acetone Pass Pass 95.110-24 H 4H hours 85C 0.5 3.05 None Mole Sieve MIBK/ Pass Very 76.5 10-24H 2H OXSOL 100 Slight hours Fail

[0063] TABLE 8 Overall Film Evaluations Based on Visual ObservationsSample ID Comments  1C Irregular flow pattern & lower gloss indicatesome incompatibility  2C Irregular flow pattern & high low glossindicate some incompatibility  3C Fairly good flow and gloss but brittlefilm  4C Good gloss and flow but brittle film  5C Good flow but“high-low” gloss pattern indicates incompatibility  6C Excellent gloss,good flow but brittle film  7C Good flow but “high-low” gloss patternindicates incompatibility  8C Excellent flow & gloss but brittle film 9C Good flow but “high-low” glass pattern indicates incompatibility 10CExcellent gloss, good flow but very brittle film 11C Good flow but“high-low” gloss pattern indicates incompatibility 12C Excellent gloss &flow but brittle film 13C Classic example of “high low” gloss pattern &incompatibility 14C Excellent gloss & flow but brittle film 15C Goodflow but poor gloss 16C Good gloss, excellent flow but brittle film 17CGood flow, poor gloss, good flexibility 18C Good flow & gloss but slighthaze; brittle film 19C Excellent flow but poor gloss; flexible film 20CExcellent gloss & flow but brittle film 21C Excellent flow but poorgloss; flexible film 22C Excellent flow & good but brittle film 23C Goodflow, poor gloss but brittle film 24C Outstanding gloss & flow butbrittle film 25C Poor gloss & flow; blush 26C Excellent gloss, moderateflow; brittle film 27C Low gloss, moderately good flow; blush; flexiblefilm 28C Fairly good flow but irregular gloss indicates incompatibility29C Poor gloss; blush, but good flexible film 30C Excellent gloss;irregular flow; brittle film 31C Very poor gloss; film soft, mars easily32C Excellent gloss; erratic flow pattern; flexible film 33C Poor flowpattern, low gloss due to incompatibility 34C Outstanding gloss, flowhardness & flexibility (*) 35C Classic “high-low” gloss pattern ofincompatibility 36C Outstanding gloss, erratic flow pattern; brittlefilm 37C “high-low” gloss, erratic flow reflects incompatibility 38CGood gloss & flow but brittle film 39C “High-low” gloss, erratic flowreflects incompatibility 40C Excellent gloss, slightly erratic flow, butgood flexibility 41C High-low gloss, erratic flow; incompatibility,flexible film 42C Outstanding gloss & flow; brittle film 43C “High-low”gloss; erratic flow reflect incompatibility 44C Outstanding gloss,good-flow but brittle film 45C Poor gloss, “high-low” gloss;incompatible but flexible 46C Outstanding gloss, good flow but brittlefilm 47C Poor gloss (“high-low”) reflect incompatibility flexible film48C Outstanding gloss, very good flow but brittle film 49C Good flowpattern & flexibility but poor gloss 50C Very good gloss & flow butbrittle film 51C Good flow & flexibility but poor gloss 52C Good gloss;fairly good flow but brittle film 53C Classic “high-low” gloss pattern;incompatible flexible film 54C Outstanding gloss; very good flow butbrittle film 55C Poor flow and gloss; incompatible but flexible film 56CVery good gloss, flow and relatively good flexibility 57C Poor flow &gloss; incompatible but flexible film 58C Outstanding gloss, flow,hardness & flexibility * 59C Poor flow & gloss; blush, but flexible film60C Good gloss & flow but brittle film 61C Good flow but poor glossflexible film 62C Good gloss & glow but brittle film 63C Poor gloss &flow; incompatible but flexible films 64C Excellent gloss & flow butbrittle film 65C Poor gloss and flow; soft film; mars easily; blush 66CVery good gloss, flow & flexibility 67C Poor gloss; good flow & flexiblefilm 68C Very good gloss, flow, hardness & flexibility * 69C Poor gloss;film soft; mars easily, flexible film 70C Good gloss & flow but brittlefilm 71C Poor gloss; film soft, mars easily but flexible 72C Gloss &flexibility good but “mottled” flow is a problem 73C Poor gloss, poorflow film soft & mars easily 74C Very good gloss, flow, hardness &flexibility * 75C “High-low” gloss pattern reflects incompatibility 76CExcellent gloss slightly erratic flow & brittle film 77C Classic“high-low” gloss incompatibility 78C Very good gloss, flow, hardness &flexibility * 79C Nice looking film but poor gloss; film flexible 80CVery good gloss, flow, hardness & flexibility * 81C Nice looking filmbut poor gloss, film flexible 82C Good gloss & flow, hardness &flexibility 83C “High-low” gloss pattern reflects incompatibility 84CVery good gloss, flow, hardness & flexibility * 85C Nice looking filmbut haze hinders gloss flexible.

[0064] After 30 days of accelerated aging, thirty-five of theeighty-five formulation evaluated had measured viscosities of 16 stokesor less, as shown in Table 9. The VOC level of these formulations rangedfrom 1.22 to 3.05 lbs/gal.

[0065] Of those 35 formulations, 29 had viscosities of 7 stokes or less,as shown in Table 10. The VOC level for these formulations ranged from1.36 to 3.05 lbs/gal.

[0066] Of the 29 formulations with viscosities of 7 stokes or less, 12contained Incosol-2® as a water scavenger, 12 contained no waterscavenger, and five contained mole sieves. Only the mole sieves weretested in combination with the reactive diluenttrimethylolpropanetriacrylate (TMPTA). The formulations containing TMPTAgelled faster than formulations without TMPTA, regardless of thesolvent. In addition, six of the 20 TMPTA/mole sieve formulationsremained sprayable after thirty days of accelerated aging. None of thesamples containing TMPTA without mole sieves maintained acceptableviscosities after thirty days of accelerated aging.

[0067] Five formulations had a viscosity of 1.25 stokes or less andremained water-like. The VOC level for these formulations ranged from1.41 to 3.05 lbs/gal. Samples 13C, 53C, 63C, and 73C contained acetoneas a solvent and sample 85C contained equal parts of acetone andp-chlorobenzotrifluoride as a solvent. None of the five samplescontained a multifunctional reactive diluent. Thin films made from theseformulations were characterized by low gloss and inadequate hardness.

[0068] Draw-down panels were prepared with a #54 wire bound rod overBonderite 1000 iron phosphate treated steel panels that were3″×6″×0.0032″. The panels were held at a constant temperature of 75°F./50 RH and then observed at two-hour increments for ten hours todetermine drying time. The majority of the panels required 10-12 hoursor more before they were dry to the touch. The samples evaluated in thefirst phase using the same ketimine dried in 8-10 hours. The slowerdrying time is attributable to three factors. First, formulations in thesecond phase had a 2.5 wt % excess amine instead of 5 wt % as used inthe first phase experiments. Second, the average coating thickness was1.83 mils, due to the higher percent solids associated with the panel,rather than about 0.8 mils as in the previous panels. Finally, theconstant temperature room was 73° F./45% RH during the thin film dryperiod, whereas, the previous panels were maintained in a constanttemperature room at 75° F./50% RH. These conditions are slightly lessfavorable and would slightly retard cure time.

[0069] Comparing the effects of the reactive diluents on the coatings,the panels containing TMPTA as a reactive diluent had better hardnessand gloss. Among the Epodil™ reactive modifiers, Epodil™ 757, abifunctional epoxy resin, also exhibited good gloss and hardness. Sincethe other reactive diluents are monofunctional, these results areconsistent with conventional coating chemistry. In summary, independentof VOC levels and storage stability, many test panels show excellenthardness and gloss while still maintaining sufficient flexibility topass the impact testing.

[0070] Four formulations remained sprayable after 30 days of acceleratedaging at 55° C. regardless of base solvent, had gloss values of greaterthan or equal to 85, passed both 20/40 pound impact testing, and had apencil hardness of greater than or equal to H after 1 week. The fourformulations that met the above criteria are 58C, 68C, 74C, and 84C. Twoof these contain MPK as a solvent (Samples 58C and 68C), and two containacetone (Samples 74C and 84C). The viscosity of both MPK formulationswas 13 stokes at day 30, which puts the viscosities around the middle ofthe acceptable range. As a result, these formulations should remaineasily sprayable for months, have acceptable VOC levels (2.7 and 2.69lbs/gal, respectively), and good physical properties. Samples 74C and84C have very low VOC levels (1.62 and 1.63 lbs/gal, respectively) andretained near water-like viscosities after accelerated aging for 30days. Many of the samples maintained acceptable viscosities for aboutsix months or more, based on accelerated aging projection, withacceptable physicals and VOC levels. TABLE 9 Formulations WithViscosities ≦ 16 Stokes After 30 Days of Accelerated Aging At 55° C.Sample Viscosity at Reactive Solvent DIT Hardness ID 30 Days VOC DiluentScavenger System 20 Gloss (1 WK)  5C 5.5 2.69 742 None MIBK Pass 47.5 H 7C 3.2 2.69 742 None MPK Pass 52.5 2H 13C 0.85 1.53 742 None AcetonePass 45.1 2H 15C 2.8 2.69 746 None MIBK Pass 38.3 2H 17C 2.5 2.69 746None MPK Pass 34.9 F 21C 6.8 1.44 746 None t-Butyl Pass 45.4 2H Acetate23C 2.25 1.49 746 None Acetone Pass 25.5 F 25C 1.65 2.7 748 None MIBKPass 17.6 F 27C 2 2.7 748 None MPK Pass 31 HB 29C 13 1.22 748 None OXSOL100 Pass 29.1 HB 31C 5.5 1.37 748 None t-Butyl Pass 17.3 <B Acetate 33C1.4 1.42 748 None Acetone Pass 33.2 F 37C 13 2.69 757 None MPK Pass 52.62H 43C 4.4 1.58 757 None Acetone Pass 60.8 H 45C 5.5 2.69 742 IncosolMIBK Pass 35 B 47C 3.2 2.69 742 Incosol MPK Pass 29.6 <B 51C 13 1.46 742Incosol t-Butyl Pass 54.5 HB Acetate 53C 0.85 1.52 742 Incosol AcetonePass 42.5 F 54C 2.8 1.67 742/TMPTA Mole Sieve Acetone Pass 101.2 4H 55C2.5 2.69 746 Incosol MIBK Pass 32.3 HB 57C 1.65 2.69 746 Incosol MPKPass 21 B 58C 13 2.7 746/TMPTA Mole Sieve MPK Pass 94.5 4H 61C 5.5 1.43746 Incosol t-Butyl Pass 38.5 H Acetate 63C 1.25 1.48 746 IncosolAcetone Pass 24.4 F 64C 3.7 1.63 746/TMPTA Mole Sieve Acetone Pass 99.24H 65C 2.25 2.7 748 Incosol MIBK Pass 16.9 B 67C 1.4 2.7 748 Incosol MPKPass 15.3 B 68C 13 2.69 748/TMPTA Mole Sieve MPK Pass 96.2 2H 71C 4.71.36 748 Incosol t-Butyl Pass 22.8 F Acetate 73C 0.65 1.41 748 IncosolAcetone Pass 36.9 <B 74C 3.7 1.62 748/TMPTA Mole Sieve Acetone Pass 914H 77C 9 2.69 757 Incosol MPK Pass 45.5 F 83C 2.5 1.68 757 IncosolAcetone Pass 49.6 F 84C 5.5 1.63 757/TMPTA Mole Sieve Acetone Pass 95.14H 85C 0.5 3.05 None Mole Sieve MIBK/ Pass 76.5 2H Oxsol 100

[0071] TABLE 10 Formulations With Viscosities ≦ 7 Stokes After 30 Daysof Accelerated Aging At 55° C. Sample Viscosity Reactive Solvent DITHardness Hardness ID @ 30 days VOC Diluent Scavenger System 20 DIT 40Gloss (24H) (1 WK)  5C 5.5 2.69 742 None MIBK Pass Pass 47.5 <B H  7C3.2 2.69 742 None MPK Pass Pass 52.5 <B 2H 13C 0.85 1.53 742 NoneAcetone Pass Slight Failure 45.1 H 2H 15C 2.8 2.69 746 None MIBK PassPass 38.3 <B 2H 17C 2.5 2.69 746 None MPK Pass Pass 34.9 <B F 21C 6.81.44 746 None t-Butyl Acetate Pass Pass 45.4 <B 2H 23C 2.25 1.49 746None Acetone Pass Pass 25.5 <B F 25C 1.65 2.7 748 None MIBK Pass Pass17.6 <B F 27C 2 2.7 748 None MPK Pass Pass 31 <B HB 31C 5.5 1.37 748None t-Butyl Acetate Pass Pass 17.3 <B <B 33C 1.4 1.42 748 None AcetonePass Pass 33.2 <B F 43C 4.4 1.58 757 None Acetone Pass Slight Failure60.8 H H 45C 5.5 2.69 742 Incosol MIBK Pass Pass 35 <B B 47C 3.2 2.69742 Incosol MPK Pass Pass 29.6 <B <B 53C 0.85 1.52 742 Incosol AcetonePass Very Slight 42.5 <B F Fail 54C 2.8 1.67 742/TMPTA Mole SieveAcetone Pass Fail 101.2 2H 4H 55C 2.5 2.69 746 Incosol MIBK Pass Pass32.3 <B HB 57C 1.65 2.69 746 Incosol MPK Pass Pass 21 <B B 61C 5.5 1.43746 Incosol t-Butyl Acetate Pass Fail 38.5 F H 63C 1.25 1.48 746 IncosolAcetone Pass Pass 24.4 F F 64C 3.7 1.63 746/TMPTA Mole Sieve AcetonePass Slight Failure 99.2 2H 4H 65C 2.25 2.7 748 Incosol MIBK Pass Pass16.9 H B 67C 1.4 2.7 748 Incosol MPK Pass Pass 15.3 <B B 71C 4.7 1.36748 Incosol t-Butyl Acetate Pass Pass 22.8 <B F 73C 0.65 1.41 748Incosol Acetone Pass Pass 36.9 <B <B 74C 3.7 1.62 748/TMPTA Mole SieveAcetone Pass Pass 91 H 4H 83C 2.5 1.68 757 Incosol Acetone Pass SlightFailure 49.6 F F 84C 5.5 1.63 757/TMPTA Mole Sieve Acetone Pass Pass95.1 H 4H 85C 0.5 3.05 None Mole Sieve MIBK/Oxsol Pass Very Slight 76.5H 2H 100 Fail

[0072] The effect of different solvents was also evaluated. Table 11shows the effect of various solvents using two different blocked amines:DETA blocked with MIBK, and xylylenediamine blocked with MIBK. Thesolvents from best to worst, regardless of reactive modifier or waterscavenger, with respect to hindering gelation were: acetone, MPK, MIBK,t-butyl acetate, and p-chlorobenzotrifluoride. The inability of t-butylacetate to hinder gelation could be due to the presence of 0.5-1.0%t-butyl alcohol, an impurity that could react with the epoxy resin.

[0073] A mixed solvent system comprised of equal partsp-chlorobenzotrifluoride/MIBK was evaluated (Sample 85C). Theformulation showed no increase in viscosity after 30 day of acceleratedaging. The calculated VOC level of the formulation was 3.05 lbs/gal,which is slightly higher than the target value of 2.8 lbs/gal. Otherphysical property values were good. Sample 85C displayed no viscosityincrease although p-chlorobenzotrifluoride alone is the least effectivesolvent at retarding gelation.

[0074] Although not wishing to be bound by theory, we believe that theseresults are a function of the polarity and hydrogen bonding of thesolvents. Table 12 shows a ranking of solvents and their polaritysolubility parameters and hydrogen bonding solubility parameters. Oxygencontaining solvent systems having both intermediate to high polarity (äPof 6-14) and high hydrogen bonding (äH of 9-14) are unacceptable forstable coating formulations. Systems with both low polarity (äP of 1-2)and low to intermediate hydrogen bonding capabilities (äH of 2-7) havepoor capacity to stabilize a blocked amine epoxy coating precursor.Oxygenated solvents with intermediate polarity (äP of 5-10) andintermediate hydrogen bonding (äH of 4-7) are acceptable for stablesingle component epoxy coating precursors.

[0075] Thus, single component epoxy coating precursors made from blockedamines having an extended shelf life have been demonstrated. Coatingscan made from these precursors having VOC levels of less than 3 lbs/gal.

[0076] Coating formulations made according to the present invention maycontain additional components, including, but not limited to, pigments,such as titanium dioxide, fillers, such as silica, and other formulationaids, such as wetting agents, defoamers, flow aids, leveling agents, andthe like. TABLE 11 Effect of Solvent System on High Temperature StorageStability and Solution Viscosity Ketimine + Stability at 55° C. EpoxyResin Solvent (Viscosity) (Stokes) DETA-MIBK Toluene None MIBK Sprayableafter 15 days 50/50 Toluene/MIBK None Xylylenediamine- MIBK (a) 19 after30 days MIBK MIBK (b) 5.5 after 30 days MPK (c) 3.2 after 30 daysp-chlorobenzotri- gelled after 30 days fluoride (d) 50/50 MIBK/p- 0.5after 30 days chlorobenzotri- fluoride (e) t-butyl acetate (f) 13 after30 days acetone (g) 0.85 after 30 days

[0077] TABLE 12 Ranking of Solvents for Stability ofXylylenediamine-MIBK Epoxy Coatings Hydrogen Polarity Bonding SolventsRanking (äP) (äH) Acetone Good 10.4 7 MIBK ″ 6.1 4.1 MPK ″ — — EthylAcetate ″ 5.3 7.2 Dioxane Poor 1.8 7.4 T-butyl acetate ″ — — Toluene ″1.4 2 P-chlorobenzo Unacceptable — — trifluoride Dimethylformamide ″13.7 11.3 Benzyl Alcohol ″ 6.3 13.7

[0078] While certain representative embodiments and details have beenshown for purposes of illustrating the invention, it will be apparent tothose skilled in the art that various changes in the compositions andmethods disclosed herein may be made without departing from the scope ofthe invention, which is defined in the appended claims.

What is claimed is:
 1. A method for making a blocked amine comprising:mixing a solvent capable of forming an azeotrope with water, an amine,and an amine blocker selected from ketones and aldehydes in a reactionvessel to form a reaction mixture; removing ambient moisture from thereaction vessel; reacting the amine and the amine blocker to form theblocked amine and water of reaction; removing the water of reaction fromthe reaction mixture while the amine and the amine blocker are reacted;and recovering the blocked amine while maintaining the absence ofmoisture.
 2. The method of claim 1 wherein the water of reaction isremoved for a length of time until 100% of a theoretical water ofreaction is removed from the reaction mixture.
 3. The method of claim 1wherein the water of reaction is removed for a length of time until thewater of reaction ceases to azeotrope.
 4. The method of claim 1 furthercomprising heating the reaction mixture until the water of reaction isremoved.
 5. The method of claim 4 further comprising cooling thereaction mixture after the water of reaction has been removed.
 6. Themethod of claim 5 further comprising heating the reaction mixture andplacing the reaction mixture under a vacuum after the water of reactionhas been removed.
 7. The method of claim 1 wherein the solvent capableof forming an azeotrope with water is capable of forming a binary orternary azeotrope with water.
 8. The method of claim 1 wherein thesolvent capable of forming an azeotrope with water is selected fromtoluene, xylene and combinations thereof.
 9. The method of claim 1wherein the solvent capable of forming an azeotrope with water comprisestoluene.
 10. The method of claim 1 wherein the amine comprises apolyamine.
 11. The method of claim 1 wherein the amine is selected fromdiethylenetriamine, m-xylylenediamine and combinations thereof.
 12. Themethod of claim 1 wherein the amine comprises m-xylylenediamine.
 13. Themethod of claim 1 wherein the amine blocker is a ketone.
 14. The methodof claim 13 wherein the ketone has a molecular weight in the range ofabout 30 to about
 600. 15. The method of claim 13 wherein the ketonecontains between about 3 and 14 carbon atoms.
 16. The method of claim 13wherein the ketone is selected from methyl isobutyl ketone, methyl ethylketone, acetone, phorone, heptanedione, tetramethylheptanedione,adamantone, acetonyl acetone, methylpropylketone and combinationsthereof.
 17. The method of claim 13 wherein the ketone comprises methylisobutyl ketone.
 18. The method of claim 1 wherein the amine blocker isan aldehyde.
 19. The method of claim 18 wherein the aldehyde has amolecular weight in the range of about 30 to about
 600. 20. The methodof claim 18 wherein the aldehyde contains between about 2 and 14 carbonatoms.
 21. The method of claim 18 wherein the aldehyde is selected frombenzaldehyde, salicylaldehyde and combinations thereof.
 22. The methodof claim 18 wherein the aldehyde comprises benzaldehyde.
 23. The methodof claim 1 wherein the solvent capable of forming an azeotrope withwater comprises toluene, the amine comprises m-xylylenediamine, and theamine blocker comprises methyl isobutyl ketone.
 24. The method of claim1 wherein the yield of blocked amine is greater than about 90% of thetheoretical yield.
 25. The method of claim 1 wherein the yield ofblocked amine is greater than about 95% of the theoretical yield. 26.The method of claim 1 wherein the yield of blocked amine is greater thanabout 97% of the theoretical yield.
 27. The product produced by themethod of claim
 1. 28. The method of claim 1 with the proviso that theblocked amine is not the reaction product of one or more compoundscontaining at least one epoxy group and one or more imines having atleast one amino hydrogen.
 29. The method of claim 1 with the provisothat the blocked amine is not a heterocycle-containing compound having abackbone chain selected from the group consisting of polyether,polyvinyl, polyester, polyamide, polycarbonate, and novalac chains andat least two heterocyclic groups of the following general formula asside chains,

wherein R¹ and R² may be the same or different and each representshydrogen, straight chain or branched C₁ to C₆ alkyl or alkenyl, or C₆ toC₈ aryl; or R¹ and R² taken together with the adjacent carbon atom,represents C₅ to C₇ cycloalkyl: R³ represents C₁ to C₁₀ alkylene.